Simple Swerve/Crab

[Rob2713g]

After reading numerous threads and ideas, I had a few questions about swerve and crab drive.

Did anyone use a Banebots gearbox in their swerve assembly this year?

What material is best for making a module? And in what thickness? I noticed some people used Delrin, while others used metal. If you used Delrin, would you need bearings?

What are the advantages to having the modules set up in pairs, as opposed to having one motor control the direction of all 4 wheels?

What size are your modules and how do you have them supported to protect them?

Thanks in advance!

[Stephen Kowski]

I'm not sure what is "best" really depends on what you are using and how, but last year ours were made from bent 1/8" ours were surrounded by 1X1 square extrustion

module
http://flickr.com/photos/jskowski/91...7594544781064/

frame:
http://flickr.com/photos/jskowski/99...7594544781064/

good luck

[zander_108]

Originally Posted by Stephen Kowski

I'm not sure what is "best" really depends on what you are using and how, but last year ours were made from bent 1/8" ours were surrounded by 1X1 square extrustion

module
http://flickr.com/photos/jskowski/91...7594544781064/

frame:
http://flickr.com/photos/jskowski/99...7594544781064/

good luck

wow, that's a really nice drivetrain...

[GMKlenklen]

Although i have never made a swervedrive, drivetrians are my "area of expertese" (although take that with a grain of salt, because i have only actually built one)
Assuming you can get any material that exists, i'd then start considering what you can do with it (what tools you have, how complex the cut outs can be, etc.) If you don't have a cnc mill, or a mill at all, then maybe some crazy aluminum contraption isn't the best for your team. Just ask the people who would be cutting/bending the meterial. lighter would be better, however, considering that a swerve drive is going to be a bit hevyer than kitbot drivetrains (generally more material and more complexity/parts)

There is a diference between independent (or paired) controll of modual rotation with respect to robot frame, and then haveing "one motor" like you said controlling all moduals, such that they all point the same way no matter what.
basically:
Independent controll means more motors, and slightly more freedom/complexity for the driver. also mechanically redundent as long as your wheels can be powered forward and back independently.
"one motor" controll means less motors, and generally makes things easyer on the driver. however to rotate the robot around an axis, two wheels will have to turn forwards, while two wheels turn backwards. lots of skiff here, because it's impossible to posititon wheels at a tangent to the "circle" your rotateing about. I hope you understand what i'm saying here.

Because i've never intended to make a swerve drive ( i prefer "holonomic" drives (mechanum or all omni-wheels)) i haven't the slightest clue how to mount a modual. I'd go find someone from "bomb squad" team #16. this year they sported a 3 wheeled swerve drive at the kansas city regional. they'll have some time to talk because I don't remember them winning anythng, although i don't know if they are goign to nat's just becasue.

hope that helps...

[meatmanek]

Originally Posted by GMKlenklen

Independent controll means more motors, and slightly more freedom/complexity for the driver. also mechanically redundent as long as your wheels can be powered forward and back independently.

Putting more functions on the bot should not make the driver's job more difficult.
A good programmer should be able to make nice interface from a simple 3-axis joystick. Push forward to go forward, push sideways to go sideways, rotate it to turn. Bonus points for using the gyro to make directions relative to the driver rather than the bot. (Careful, though, you may have to buy a faster gyro - the KOP gyro maxes out at 80 degrees/second. Found that out the hard way.)